I always heard that the phrase "the whole 9 yards" was a reference to the length of the ammo belts for WWII era fighter plane machine guns but I've also heard some claim it had to do with the length of tartan used to make a kilt. According to this article though, we might all be wrong ...

http://www.nytimes.com/2012/12/27/bo...=fb-share&_r=0